1. Field of the Invention
The present invention relates to a method and apparatus for preparing bone grafts for use in the repair, replacement, and/or augmentation of various portions of animal or human skeletal systems. More particularly, the present invention relates to prepared bone grafts, guides for forming bone grafts and methods for forming bone grafts.
2. Brief Description of the Prior Art
Several procedures involve the use and implantation of bone into an animal or human body. Generally, benefits of implanted bone include, but are not limited to, providing support, promoting healing, filling cavities, separating or spacing bony elements such as vertebral bodies, promoting fusion, and stabilizing the site of fractures.
Although the use of bone grafts is not limited to the spine, bone grafts are frequently implanted during certain surgical procedures to promote surgical decompression and/or stabilization of the spine. Such procedures include, but are not necessarily limited to, spinal discectomy with fusion and postcorpectomy reconstruction. In such procedures, autogenic, allogenic or xenogenic bone or synthetic material can be used to provide structural support in voids where diseased or damaged tissue or bone has been removed from the spine.
During such procedures, it is often critically important that the size and geometry of the implanted bone be consistent with the void into which said implanted bone is ultimately introduced. Put another way, the success of such procedures frequently depend, at least in large part, on the degree to which the size and geometry of an implanted bone section matches the void that will receive said bone section.
Practitioners generally have a number of different options available when choosing inter-body fusion implants. Such implants can basically be segregated into two groups: mechanical devices and actual bone. When using actual bone implants, practitioners can utilize pre-processed bone grafts that are currently available in a number of different configurations and geometries. Alternatively, practitioners can prepare implant grafts intra-operatively using a section of donor bone. Autogenic grafts, by their very nature, must be prepared intra-operatively.
Some practitioners prefer intra-operative graft preparation. Even when measurements translated from pre-operative non-invasive imagery are used to determine appropriate graft geometry, intra-operative measurement is still required to ensure proper fit of a particular graft. Intra-operative bone graft preparation allows a surgeon to customize an implant to fit a particular application. Some practitioners will even modify pre-processed bone grafts prior to insertion.
Alternatively, a section of a bone can be taken directly from the patient receiving the implant. In such cases, a “donor” bone (known as an “autograft”) is harvested from another part of a patient's body and used as in implant during the surgical procedure. However, the autograft is frequently longer and/or shaped differently than the required bone implant. Thus, the donor bone often must be cut to precise lengths and/or at precise angles.
When using a patient's donor bone, it is frequently necessary to form required bone implant sections directly in the intra-operative environment such as the operating room itself. Moreover, multiple graft implants are frequently required. To minimize trauma associated with autographic bone harvesting, it is typically advantageous to form multiple graft sections from the same donor bone.
Thus, there is a need for a simple, inexpensive and effective method and apparatus for the manufacture of bone implants directly in an intra-operative environment. The subject apparatus should allow a surgeon to produce, and thereafter faithfully reproduce, grafts with a high degree of precision. The subject apparatus should be robust, durable, easy to use, consistent with surgical environment(s) and compatible with existing cutting tools.